  Apparently it's a legal requirement that at least one up escalator is in service in a tube station at a time so that the bodies of people crushed, maimed and injured in an emergency evacuation can be dispensed to rescue services at the top.
But I suspect that the escalators at Archway tube have an additional contractual obligation: at least one of them has to be taken out of service once every three months without fail just in case the station's users get used to a reliable service. I think they should stop this practice at once. I'm scaring far too many people by whooping and going "wheeeeeeeeeeeeee" as I plunge down the spiral staircase at a rate of knots. One day there may be casualties. 
